Method of manufacturing a flame-retardant heat insulating formed product

ABSTRACT

A method of manufacturing a flame-retardant heat insulating formed product in the shape of a mat includes pouring water in used paper or a pulp material to defibrate and obtain defibrated cotton. A flame retardant such as a boric acid is charged into the defibrated cotton. By stirring and heating, a flame-retardant heat insulating defibrated cotton is obtained. Short fibers with a low melting point made of polyester or the like are charged into the flame-retardant heat insulating defibrated cotton. By mixing and stirring, a flame-retardant heat insulating loose material is obtained. A forming die made of corrugated cardboard provided with a lid having air vents is filled with the flame-retardant heat insulating loose material. The flame-retardant heat insulating loose material together with the forming die are heated with a microwave heating apparatus to form. A mat-shaped formed product is removed from the forming die.

TECHNICAL FIELD

The present invention relates to a method of manufacturing aflame-retardant heat insulating formed product in the shape of a mat andthe like.

BACKGROUND ART

As heat insulating materials used in a wall, ceiling and the like of astructure, glass wool, rock wool and the like, which are inexpensive andgood in workability, are used. However, the glass wool and the like haveproblems with a hygiene perspective, and since recycling is difficult,are not good for the environment.

On the other hand, cellulose fibers obtained by defibrating paper suchas used paper are excellent as heat insulating materials, but areexpensive. Further, in construction, since work is performed by ablowing scheme, dust tends to occur and is bad for the environment, andthere is a drawback that workability is poor.

In view of the aforementioned respect, as heat insulating materials ofstructures, glass wool and the like are used in almost constructionexamples.

In terms of such a background, the inventor of the present inventionimproved problems of conventional heat insulating materials, and hasproposed a heat insulating material which has a sound insulation effectand flame-retardant effect, and is excellent in construction workabilityand economic efficiency. Further, the heat insulating material enablesthe material to be recycled, and therefore, is also excellent inenvironmental characteristics (see Patent Document 1).

The general outlines of the proposed heat insulating material are asdescribed below.

(1) A heat insulating material prepared by stirring and mixing cellulosefibers obtained by defibrating paper and cotton-shaped synthetic fiberswith polypropylene as the main ingredient, and further mixing boric acidand borax.(2) A mat-shaped formed product for storing the above-mentioned heatinsulating material to apply the heat insulating material to a wall andceiling of a structure (see FIGS. 2 and 3).

Manufacturing of the Heat Insulating Material

(1) Paper such as used paper is defibrated to prepare cellulose fibers.(2) Synthetic fibers with polypropylene as the main ingredient areprepared and crushed into cotton shapes.(3) The heat insulating material of a structure is obtained by stirringand mixing the cellulose fibers prepared in the step of above-mentioned(1) and cotton-shaped synthetic fibers with polypropylene as the mainingredient prepared in the step of above-mentioned (2). Further, boricacid and borax are mixed.

Manufacturing of the Mat-Shaped Formed Product

Manufacturing of the mat-shaped formed product filled with the heatinsulating material as a loose material will be described with referenceto FIGS. 2 and 3.

FIG. 2 is a perspective view of the mat-shaped formed product, and FIG.3 is a cross-sectional view along the line A-A of FIG. 2.

Three end portions of a bag body 2 of two overlapped nonwoven fabric,paper, film or the like are joined by a method using sewing, melting,adhesive or the like.

An opened end portion of the bag body 2 is opened to fill with a loosematerial 4 made of the heat insulating material, and the opened endportion is joined by a method using sewing, melting, adhesive or thelike to prepare the mat-shaped formed product.

PRIOR ART DOCUMENT Patent Document

[Patent Document 1] Japanese Unexamined Patent Publication No.2017-89208

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

In the method of manufacturing the formed product shown in FIGS. 2 and 3proposed previously, since the following steps are required, there hasbeen a drawback that the formed product is high in cost.

(1) Step of joining three end portions of a bag body 2 of two overlappednonwoven fabric, paper, film or the like by a method using sewing,melting, adhesive or the like.(2) Step of opening an opened end portion of the bag body 2 to fill witha loose material 4, and joining the opened end portion by a method usingsewing, melting, adhesive or the like.

Accordingly, it is an object of the present invention to provide amethod of manufacturing a flame-retardant heat insulating formed productin the shape of a mat and the like which has a sound insulation effect,is excellent in environmental characteristics and is excellent ineconomic efficiency with the manufacturing steps simplified.

Means for Solving the Problem

The means for attaining the object of the present invention is asdescribed below.

(1) A method of manufacturing a flame-retardant heat insulating formedproduct, including the step of pouring water in used paper or a pulpmaterial to defibrate and obtain defibrated cotton, the step of charginga flame retardant into the defibrated cotton, and by stirring andheating, obtaining flame-retardant heat insulating defibrated cotton,the step of charging short fibers with a low melting point into theflame-retardant heat insulating defibrated cotton, and by mixing andstirring, obtaining a flame-retardant heat insulating loose material,the step of filling a forming die made of paper provided with a lid withthe flame-retardant heat insulating loose material, the step of heatingthe flame-retardant heat insulating loose material together with theforming die with a microwave heating apparatus to form, and the step ofremoving a formed product from the forming die.(2) The method of manufacturing a flame-retardant heat insulating formedproduct as described in (1), characterized in that the forming die madeof paper is a forming die made of corrugated cardboard.(3) The method of manufacturing a flame-retardant heat insulating formedproduct as described in (1) or (2), characterized in that the lid of theforming die is a lid having an air vent.(4) The method of manufacturing a flame-retardant heat insulating formedproduct as described in any one of (1) to (3), characterized in that theflame retardant is a boric acid or boron.(5) The method of manufacturing a flame-retardant heat insulating formedproduct as described in any one of (1) to (4), characterized in that theshort fibers with a low melting point are made of polyester,polyethylene or polypropylene.(6) The method of manufacturing a flame-retardant heat insulating formedproduct as described in any one of (1) to (5), characterized in that theflame-retardant heat insulating formed product is a mat-shaped formedproduct.

Advantageous Effect of the Invention

According to the present invention, raw materials of the forming die tomanufacture the flame-retardant heat insulating formed product may bepaper such as corrugated cardboard commonly used in packing and thelike. Then, since a forming die formed from a metal die or wood die isnot used, it is possible to promptly manufacture the forming die, and toobtain the flame-retardant heat insulating formed product having thesound insulation effect at very low cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 contains schematic diagrams to explain a method of manufacturinga flame-retardant heat insulating formed product according to thepresent invention;

FIG. 2 is a perspective view of a mat-shaped formed product filled witha heat insulating material as a loose material; and

FIG. 3 is a cross-sectional view along the line A-A of FIG. 2.

BEST MODE FOR CARRYING OUT THE INVENTION

A mat-shaped flame-retardant heat insulating formed product will beexemplified as a flame-retardant heat insulating formed product todescribe a manufacturing method thereof.

FIGS. 1A to 1C are schematic diagrams to explain steps up tomanufacturing of a flame-retardant heat insulating loose material.

Further, FIGS. 1D and 1E are schematic diagrams to explain steps up tomanufacturing of a forming die made of paper, and FIGS. 1F to 1H areschematic diagrams to explain steps of from filling the prepared formingdie made of paper with the flame-retardant heat insulating loosematerial to obtaining a flame-retardant heat insulating formed product.

Manufacturing of the Flame-Retardant Heat Insulating Loose Material

In manufacturing of the flame-retardant heat insulating loose material,as shown in FIG. 1A, first, water is poured in used paper or a pulpmaterial to defibrate and obtain defibrated cotton.

Next, as shown in FIG. 1B, a flame retardant such as boric acid andboron is charged into the defibrated cotton, and by stirring andheating, flame-retardant heat insulating defibrated cotton is obtained.

Further, as shown in FIG. 1C, short fibers with a low melting point suchas polyester, polyethylene and polypropylene are charged into theflame-retardant heat insulating defibrated cotton, and by mixing andstirring, the flame-retardant heat insulating loose material isobtained.

Manufacturing of the Forming Die

The forming die is provided with a lid having a plurality of air vents,and is configured to be structure where the thickness is thin, ascompared with the vertical and horizontal lengths.

Corrugated cardboard made of paper commonly used in packing and the likeis prepared, is subjected to cutting creasing processing according to adevelopment diagram as shown in FIG. 1D as one example, and next, isbuilt to be the forming die made of paper having a lid as shown in FIG.1E.

One example of the forming die made of paper is as shown in FIG. 1E, andvarious shapes are considered as its shape, and are selected asappropriate corresponding to a shape of a required flame-retardant heatinsulating formed product.

It is preferable that the thickness of the corrugated cardboard requiredof the forming die is about 3 mm in the case where the sum of verticaland horizontal lengths and thickness is about 100 cm, is about 5 mm inthe case where the sum ranges from about 100 cm to 150 cm, and is 5 mmor more in the case where the sum is 150 cm or more.

In addition, in the case of the low number of production lots,corrugated cardboard with a thickness of 3 mm may be used.

Manufacturing of the Flame-Retardant Heat Insulating Formed Product

As shown in FIG. 1F, after filling the forming die made of paper withthe flame-retardant heat insulating loose material and compressing, thelid is put on. The lid of the forming die is to prevent the filledflame-retardant heat insulating loose material from being dissipatedfrom the upper portion, at the time of carrying and at the time ofmicrowave heating.

Further, the lid of the forming die has an effect of promoting formingby heating, on average, the flame-retardant heat insulating loosematerial filled with steam heat at the time of microwave heating.

Next, as shown in FIG. 1G, the lidded forming die filled with theflame-retardant heat insulating loose material is heated with amicrowave heating apparatus.

At the time of microwave heating, moisture of the flame-retardant heatinsulating loose material is heated and vaporized. Therefore, the lid ofthe forming die is provided with air vents for ventilation. It ispreferable that the diameter of the air vent is about 5 mm, and that aplurality of vents is provided at intervals ranging from 2 cm to 5 cm.

The short fiber with a low melting point contained in theflame-retardant heat insulating loose material reaches a melting pointby heating at a temperature of 110° C. or more. By fusing of the shortfiber with a low melting point, the flame-retardant heat insulatingloose material is mutually joined. After heating and forming with themicrowave heating apparatus, the mat-shaped formed product is removedfrom the forming die, and by natural cooling, the mat-shapedflame-retardant heat insulating formed product is obtained as shown inFIG. 1H.

Embodiment

One example of a manufacturing process of the mat-shaped formed productis as described below.

(1) In 1 kg of used paper or pulp material, water is poured in a weightratio of 30% to 45%, and the resultant is defibrated for 120 seconds to300 seconds to be defibrated cotton.(2) Into the defibrated cotton is charged 150 g of boric acid, theresultant is stirred and heated for 60 seconds to impregnate, andflame-retardant heat insulating defibrated cotton is obtained.(3) Into the flame-retardant heat insulating defibrated cotton ischarged 300 g to 800 g (30% to 80% in a weight ratio) of short fiberswith a low melting point, and the resultant is mixed and stirred for 60seconds to obtain a flame-retardant heat insulating loose material.(4) A beforehand prepared forming die made of corrugated cardboardprovided with a lid having air vents is filled with the flame-retardantheat insulating loose material.(5) The flame-retardant heat insulating loose material is heatedtogether with the forming die with a microwave heating apparatus at atemperature of 110° C. or more for 120 seconds to 600 seconds.(6) The flame-retardant heat insulating formed product made the shape ofa mat is removed from the forming die, and is subjected to naturalcooling.

In addition, in the present Description, the method of manufacturing amat-shaped formed pro duct is exemplified and described as theEmbodiment, but the formed product according to the present invention isnot limited to the mat-shaped product.

It is needless to say that any appropriate design modification iscapable of being made to manufacturing of the flame-retardant heatinsulating formed product, without departing from the scope of theclaims.

1. A method of manufacturing a flame-retardant heat insulating formedproduct, including: pouring water in used paper or a pulp material todefibrate and obtain defibrated cotton; charging a flame retardant intothe defibrated cotton, and by stirring and heating, obtainingflame-retardant heat insulating defibrated cotton; charging short fiberswith a low melting point into the flame-retardant heat insulatingdefibrated cotton, and by mixing and stirring, obtaining aflame-retardant heat insulating loose material; filling a forming diemade of paper provided with a lid with the flame-retardant heatinsulating loose material; heating the flame-retardant heat insulatingloose material together with the forming die with a microwave heatingapparatus to form; and removing a formed product from the forming die.2. The method of manufacturing a flame-retardant heat insulating formedproduct according to claim 1, wherein the forming die made of paper is aforming die made of corrugated cardboard.
 3. The method of manufacturinga flame-retardant heat insulating formed product according to claim 1,wherein the lid of the forming die has an air vent.
 4. The method ofmanufacturing a flame-retardant heat insulating formed product accordingto claim 1, wherein the flame retardant is a boric acid or boron.
 5. Themethod of manufacturing a flame-retardant heat insulating formed productaccording to claim 1, wherein the short fibers with a low melting pointare made of polyester, polyethylene or polypropylene.
 6. The method ofmanufacturing a flame-retardant heat insulating formed product accordingto claim 1, wherein the flame-retardant heat insulating formed productis a mat-shaped formed product.